1. Field of the Invention
The present invention relates to a display device for displaying an image by current-driving light-emitting elements disposed to its respective pixels, to a driving method for the display device and to an electronic apparatus including the display device. More specifically, the present invention relates to a driving method for an active matrix display device in which the current passing through a light-emitting element, such as an organic electroluminescent (EL) element, is controlled by an insulated-gate field-effect transistor in each pixel circuit.
2. Description of the Related Art
An example of such display device is a liquid crystal display in which many liquid crystal pixels are arranged in a matrix. According to image information, the liquid crystal display controls the intensity of light transmitted through or reflected by each of the pixels, and thus displays an image corresponding to the image information. An organic EL display, including organic EL elements as pixels, has a mechanism similar to that of the liquid crystal display described above. However, unlike the liquid crystal pixels of the liquid crystal display, the organic EL elements of the organic EL display are self-luminous. Therefore, the organic EL display has advantages over the liquid crystal display in that it provides better viewability, requires no backlight, and has a higher response speed. Additionally, the organic EL display is very different from the liquid crystal display in that, unlike the liquid crystal display, which is a voltage-controlled display, the organic EL display is a current-controlled display in which the luminance (gradation) of each light-emitting element is controllable by the value of a current flowing therethrough.
As in the case of the liquid crystal display, there are two types of driving methods for the organic EL display: a simple matrix type and an active matrix type. Although a simple-matrix display is simple in structure, it has problems in its large size and its difficulty achieving high definition display. Therefore, current efforts are primarily directed toward the development of active-matrix displays. In an active-matrix display, a current flowing through a light-emitting element in each pixel circuit is controlled by an active element (typically a thin-film transistor or TFT) disposed in the pixel circuit (see, for example, Japanese Unexamined Patent Application Publications Nos. 2003-255856, 2003-271095, 2004-133240, 2004-029791, 2004-093682, and 2006-215213).